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Hollyhock (Alcea rosea L.) is an aromatic, ornamental/medicinal plant species for which the selection of drought-tolerant varieties based on physio-chemical traits is desirable. The data presented resulted from a field experiment. This experiment was designed as a split-plot, based on a randomized complete block design, in which the main plots consisted of the three irrigation regimes (30, 60 and 80% permissible discharge moisture available in the soil), and the subplots consisted of nine hollyhock varieties. Photosynthetic pigments, Fv/Fm, proline content and selected antioxidant enzymes were measured throughout the period of induced drought stress. The data obtained illustrate the nature of the physiological response of hollyhock to drought stress. Based on the measured traits the varieties Isfahan 1, Shiraz 1 and Tabriz were shown to display the highest degree of resistance to drought stress. These data suggest that the effect of drought stress is dependent upon the drought level, variety and the trait in question. In this regard, future plant breeders for this species may find it useful to utilize ascorbate peroxidase (APX), catalase (CAT) and guayacol peroxidase (POX) activities as biochemical markers to select for drought-tolerant genotypes. As such, hollyhock can be considered a promising ornamental/medicinal species for cultivation in semi-arid environments. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.) yield and nutrient contents may be affected under salinity condition. Thus, this experiment was conducted to determine the effect of three salinity levels (60, 120, and 180 mM NaCl) on shoot and root dry weights, and mineral contents of three alfalfa cultivars. With the increasing salinity levels sodium (Na) and magnesium (Mg) contents increased; but potassium (K), nitrogen (N), phosphorous (P), calcium (Ca), zinc (Zn), and copper (Cu) contents and root and leaf weights decreased; however, changes in these traits depended on cultivar and salinity level. However, Rehnani, a tolerant cultivar, had the lowest Na and Mg contents and the highest K, N, P, Ca, Zn, and Cu contents and dry weights under all of the salinity levels. Moreover, leaf dry weight and leaf P content had the highest correlation with salt tolerance suggesting that these traits may be used as a marker for selecting salts that are tolerant among genotypes in alfalfa. [ABSTRACT FROM AUTHOR]

Alfalfa ( Medicago sativa L.) cultivars respond differently to drought stress levels and oxidative injury. This may provide us with an important tool to identify the chemical mechanisms operative in drought tolerant genotypes. The present experiment was conducted to determine catalase ( CAT), ascorbate peroxidase ( APX) and peroxidase ( POX) activities; malondialdehyde ( MDA) content; herbage yield; stress susceptibility index ( SSI); and drought tolerance index ( DTI) of 10 alfalfa cultivars under four irrigation regimes (55, 65, 75 and 85% depletion of available soil water). Drought stress was observed to reduce herbage yield but increase CAT, APX and POX activities as well as MDA content; however, such alterations were cultivar-drought level-specific. With a few exceptions, Baghdadi had the highest CAT, POX and APX activities and lowest MDA content, lowest reduction in herbage yield and the lowest SSI and the highest DTI under all irrigation regimes suggesting that it was the most adapted and drought-tolerant cultivar. Herbage yield had a significant and positive correlation with POX and a significant and negative correlation with MDA under all irrigation regimes indicating that they could be used as markers for selecting more drought-tolerant cultivars in alfalfa. Catalase and APX also had a significant and positive correlation with herbage yield, thus they could be used as markers for selection of more drought-tolerant cultivars. The results suggested that a wide variation in drought tolerance exists within alfalfa cultivars, thus selection for more drought tolerance is possible. In addition, chemical markers such as POX, CAT and APX activities and MDA content may be used to assist in selection for more drought tolerance cultivar in this species. [ABSTRACT FROM AUTHOR]

The study was conducted to determine the allelopathic effects of Crocus sativus L., Ricinus communis L., Nicotiana tabacum L., Datura inoxia Mill., Nerium oleander L., and Sorghum vulgare L. on the germination and growth of Amaranthus retroflexus (redroot pigweed). Powder and aqueous extracts of these plants were used to run the experiment under laboratory and greenhouse conditions. In the laboratory, all aqueous extracts showed a significant inhibitory effect on the germination, seedling length and weight of redroot pigweed plants. The most allelopathic against the redroot pigweed were R. communis, N. tabacum, and D. inoxia. In the greenhouse experiment, extracts and the powder of these plants also showed significant inhibitory effects on pigweed dry weight, height, leaf area, number of survivor plants, and amount of chlorophyll. In the germination bioassay and application of powder, the inhibitory effect was dosage dependent -- the higher the concentration, the strongest the inhibitory effect. From the obtained results, it can be concluded that the powder and extracts of the tested species have an herbicidal potential against redroot pigweed and could be used as natural herbicides and mulches. [ABSTRACT FROM AUTHOR]

Borage (Borago officinalis L. Boraginaceae) has been widely recognized as a medicinal plant with high nutritive value and for γ linolenic acid (GLA), extracted from the oil seed. Information on cultural practices for borage production is limited and evaluation of environmental factors affecting vegetative and seed yield would be required. In this study, the effect of 5 nitrogen levels including 0, 50, 100, 150 and 200 kg ha-1 on mucilage content, yield and yield components of borage was studied in a randomized complete block design with three replications. Nitrogen treatments had significant effect on the number of inflorescence per plant, the number of floret per plant, plant dry matter, flower and stem mucilage while plant height and leaf mucilage percentage were not affected by nitrogen treatment. The highest number of floret per plant as flower yield and mucilage of flower were found in 100 kg ha-1 nitrogen level. Using appropriate amount of nitrogen fertilizer is suggested to obtain higher mucilage for medicinal proposes in borage crop. [ABSTRACT FROM AUTHOR]